U.S. patent number 9,017,017 [Application Number 12/421,842] was granted by the patent office on 2015-04-28 for variable-vane assembly having fixed guide pins for unison ring.
This patent grant is currently assigned to Honeywell Internatonal Inc.. The grantee listed for this patent is Francis Abel, Pierre Barthelet, Emmanuel Bouvier, Olivier Espasa, Lorrain Sausse, Mohamed Tahyry. Invention is credited to Francis Abel, Pierre Barthelet, Emmanuel Bouvier, Olivier Espasa, Lorrain Sausse, Mohamed Tahyry.
United States Patent |
9,017,017 |
Sausse , et al. |
April 28, 2015 |
Variable-vane assembly having fixed guide pins for unison ring
Abstract
A variable-vane assembly for a variable nozzle turbine comprises
a nozzle ring supporting a plurality of vanes affixed to vane arms
that are engaged in recesses in the inner edge of a unison ring.
The unison ring is rotatable about the axis of the nozzle ring so
as to pivot the vane arms, thereby pivoting the vanes in unison. A
plurality of guide pins for the unison ring are inserted into
apertures in the nozzle ring and are rigidly affixed therein such
that the guide pins are non-rotatably secured to the nozzle ring
with a guide portion of each guide pin projecting axially from the
face of the nozzle ring. Each guide portion defines a shoulder
radially overlapping the inner edge of the unison ring such that
the unison ring is restrained by the guide pins against excessive
movement in both radial and axial directions.
Inventors: |
Sausse; Lorrain (Charmes,
FR), Barthelet; Pierre (Remiremont, FR),
Abel; Francis (Dogneville, FR), Espasa; Olivier
(Dogneville, FR), Tahyry; Mohamed (Rambervillers,
FR), Bouvier; Emmanuel (Epinal, FR) |
Applicant: |
Name |
City |
State |
Country |
Type |
Sausse; Lorrain
Barthelet; Pierre
Abel; Francis
Espasa; Olivier
Tahyry; Mohamed
Bouvier; Emmanuel |
Charmes
Remiremont
Dogneville
Dogneville
Rambervillers
Epinal |
N/A
N/A
N/A
N/A
N/A
N/A |
FR
FR
FR
FR
FR
FR |
|
|
Assignee: |
Honeywell Internatonal Inc.
(Morristown, NJ)
|
Family
ID: |
42106881 |
Appl.
No.: |
12/421,842 |
Filed: |
April 10, 2009 |
Prior Publication Data
|
|
|
|
Document
Identifier |
Publication Date |
|
US 20100260597 A1 |
Oct 14, 2010 |
|
Current U.S.
Class: |
415/160 |
Current CPC
Class: |
F01D
17/165 (20130101); F05D 2260/37 (20130101); F05D
2230/60 (20130101); F05D 2230/64 (20130101); F05D
2220/40 (20130101); Y10T 29/49323 (20150115); F05D
2250/29 (20130101); F16B 19/06 (20130101); F05D
2250/232 (20130101) |
Current International
Class: |
F01B
25/02 (20060101) |
Field of
Search: |
;415/160,151 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
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102 38 412 |
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Mar 2004 |
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DE |
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10 2004 023 209 |
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Dec 2005 |
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DE |
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10 2004 023 210 |
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Dec 2005 |
|
DE |
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10 2004 023 211 |
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Dec 2005 |
|
DE |
|
10 2004 023282 |
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Dec 2005 |
|
DE |
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10 2004 037082 |
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Mar 2006 |
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DE |
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1 156 227 |
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Nov 2001 |
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EP |
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1 422 384 |
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May 2004 |
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EP |
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WO 2008/118833 |
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Oct 2008 |
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WO |
|
Other References
European Patent Office, Notification of Transmittal of the
International Search Report and Written Opinion of the
International Searching Authority, or the Declaration, Jul. 24,
2008, all pages. cited by examiner .
European Patent Office, International Search Report, Jul. 22, 2008,
all pages. cited by examiner .
European Patent Office, Written Opinion of the International
Searching Authority, Jul. 22, 2008, all pages. cited by examiner
.
English Translation of Baar, DE 102 38 412. cited by examiner .
English Translation of Magzalci, DE 10 2004 023 209. cited by
examiner .
English Translation of Magzalci, DE 10 2004 023 211. cited by
examiner .
Communication from the European Patent Office from European Patent
Application No. 10158228.6, dated Nov. 14, 2012. cited by applicant
.
European Search Report from European Patent Application No.
10158228.6, dated Oct. 29, 2012. cited by applicant.
|
Primary Examiner: Toledo; Fernando L
Assistant Examiner: Hall; Victoria K
Attorney, Agent or Firm: James; John C.
Claims
What is claimed is:
1. A variable-vane assembly for a turbocharger, comprising: a
nozzle ring having opposite first and second faces and having a
plurality of circumferentially spaced-apart first apertures each
extending axially into the first face and a plurality of
circumferentially spaced-apart second apertures each of which
extends axially from the first face to the second face; a plurality
of vanes having respective axles received into the second apertures
from the second face of the nozzle ring and being rotatable in the
second apertures such that the vanes are rotatable about respective
axes defined by the axles, a distal end of each axle projecting out
from the respective second aperture beyond the first face; a
plurality of vane arms respectively affixed rigidly to the distal
ends of the axles, each vane arm having a free end; a unison ring
having a radially inner edge defining a plurality of recesses
therein that respectively receive the free ends of the vane arms,
the unison ring being positioned coaxially with the nozzle ring
with a face of the unison ring opposing the first face of the
nozzle ring, the unison ring being rotatable about an axis of the
nozzle ring so as to pivot the vane arms, thereby pivoting the
vanes in unison; protrusions integrally formed on the nozzle ring
and extending from the nozzle ring and contacting the unison ring,
so as to axially space the first face of the nozzle ring from the
opposing face of the unison ring by a first axial distance; and a
plurality of guide pins located radially inward of the radially
inner edge of the unison ring, the guide pins each being inserted
into a respective one of the first apertures in the nozzle ring and
being rigidly affixed therein such that the guide pins are
non-rotatably secured to the nozzle ring with a guide portion of
each guide pin projecting axially from the first face of the nozzle
ring, the guide portion of each guide pin having a shank and
defining a shoulder axially spaced from the first face of the
nozzle ring by a second axial distance greater than the first axial
distance, the shoulders radially overlapping the radially inner
edge of the unison ring, whereby the protrusions and the shoulders
cooperate to constrain axial movement of the unison ring and the
shanks constrain radial movement of the unison ring.
2. The variable-vane assembly of claim 1, wherein the protrusions
comprise bosses, each boss being adjacent a respective one of the
first apertures.
3. The variable-vane assembly of claim 2, wherein each boss
surrounds the respective first aperture.
4. The variable-vane assembly of claim 1, wherein each of the guide
pins includes an end portion that is press-fit into the respective
first aperture in the nozzle ring.
5. The variable-vane assembly of claim 4, wherein the shank of each
guide pin has a greater diameter than the end portion.
6. The variable-vane assembly of claim 1, wherein each first
aperture is located, circumferentially, between two of the second
apertures.
7. The variable-vane assembly of claim 6, wherein the first
apertures are located at a greater radius than the second
apertures, relative to the axis of the nozzle ring.
8. The variable-vane assembly of claim 1, wherein the vane arms are
affixed to the distal ends of the axles by riveted joints.
9. The variable-vane assembly of claim 8, wherein each vane arm has
a hole that receives the distal end of the associated axle, the
hole having a conical knurled portion at an upper side of the hole
facing away from the associated vane, and the distal end of the
axle is upset to generally conform in shape to that of the conical
knurled portion so as to affix the vane arm to the axle.
10. A variable-vane assembly for a turbocharger, comprising: a
nozzle ring having opposite first and second faces and having a
plurality of circumferentially spaced-apart apertures each of which
extends axially from the first face to the second face; a plurality
of vanes having respective axles received into the apertures from
the second face of the nozzle ring and being rotatable in the
apertures such that the vanes are rotatable about respective axes
defined by the axles, a distal end of each axle projecting out from
the respective aperture beyond the first face; a plurality of vane
arms respectively affixed rigidly to the distal ends of the axles,
each vane arm having a free end; and a unison ring defining a
plurality of recesses therein that respectively receive the free
ends of the vane arms, the unison ring being positioned coaxially
with the nozzle ring with a face of the unison ring opposing the
first face of the nozzle ring, the unison ring being rotatable
about an axis of the nozzle ring so as to pivot the vane arms,
thereby pivoting the vanes in unison; protrusions integrally formed
on the nozzle ring and extending from the nozzle ring and
contacting the unison ring, so as to axially space the first face
of the nozzle ring from the opposing face of the unison ring by a
first axial distance; a plurality of guide pins located radially
inward of a radially inner edge of the unison ring, the guide pins
each being inserted into a respective opening in the nozzle ring
and being rigidly affixed therein such that the guide pins are
non-rotatably secured to the nozzle ring with a guide portion of
each guide pin projecting axially from the first face of the nozzle
ring, the guide portion of each guide pin having a shank and
defining a shoulder axially spaced from the first face of the
nozzle ring by a second axial distance greater than the first axial
distance, the shoulders radially overlapping the radially inner
edge of the unison ring, whereby the protrusions and the shoulders
cooperate to constrain axial movement of the unison ring and the
shanks constrain radial movement of the unison ring; and wherein
the vane arms are affixed to the distal ends of the axles by
riveted joints, each vane arm having a hole that receives the
distal end of the associated axle, the hole having a conical
knurled portion at an upper side of the hole facing away from the
associated vane, and the distal end of the axle being upset to
generally conform in shape to that of the conical knurled portion
so as to affix the vane arm to the axle.
11. A method for assembling a variable-vane assembly for a
turbocharger, comprising the steps of: providing a nozzle ring
having opposite first and second faces, having a plurality of
circumferentially spaced-apart first apertures each extending
axially into the first face and a plurality of circumferentially
spaced-apart second apertures each of which extends axially from
the first face to the second face; providing a unison ring having a
radially inner edge defining a plurality of recesses therein, and
positioning the unison ring adjacent the first face of the nozzle
ring, substantially coaxial with the nozzle ring; providing
protrusions integrally formed on the nozzle ring and extending from
the nozzle ring and contacting the unison ring, so as to axially
space the first face of the nozzle ring from the opposing face of
the unison ring by a first axial distance; positioning a plurality
of guide pins radially inward of the radially inner edge of the
unison ring, and inserting end portions of the guide pins
respectively into the first apertures in the nozzle ring and
rigidly affixing said end portions therein such that the guide pins
are non-rotatably secured to the nozzle ring with a guide portion
of each guide pin projecting axially from the first face of the
nozzle ring, the guide portion of each guide pin having a shank and
defining a shoulder axially spaced from the first face of the
nozzle ring, the shoulders radially overlapping the radially inner
edge of the unison ring, whereby the protrusions and the shoulders
of the guide pins cooperate to constrain axial movement of the
unison ring and the shanks constrain radial movement of the unison
ring; providing a plurality of vanes having respective axles, and
inserting the axles respectively into the second apertures from the
second face of the nozzle ring such that a distal end of each axle
projects out from the respective second aperture beyond the first
face; providing a plurality of vane arms, and rigidly affixing the
vane arms respectively to the distal ends of the axles, each vane
arm having a free end; and engaging the free ends of the vane arms
respectively in the recesses defined in the inner edge of the
unison ring, whereby the unison ring is rotatable about an axis of
the nozzle ring so as to pivot the vane arms, thereby pivoting the
vanes in unison.
12. The method of claim 11, wherein the step of rigidly affixing
the vane arms to the distal ends of the axles comprises a riveting
process.
13. The method of claim 12, wherein each vane arm is provided to
have a hole for receiving the distal end of one of the axles, and
the hole is provided to have a conical knurled portion at an upper
side of the hole facing away from the associated vane, and the
affixing step comprises upsetting the distal end of the axle to
generally conform in shape to that of the conical knurled portion
so as to affix the vane arm to the axle.
Description
BACKGROUND OF THE INVENTION
The present invention relates to turbochargers having a
variable-nozzle turbine in which an array of movable vanes is
disposed in the nozzle of the turbine for regulating exhaust gas
flow into the turbine.
An exhaust gas-driven turbocharger is a device used in conjunction
with an internal combustion engine for increasing the power output
of the engine by compressing the air that is delivered to the air
intake of the engine to be mixed with fuel and burned in the
engine. A turbocharger comprises a compressor wheel mounted on one
end of a shaft in a compressor housing and a turbine wheel mounted
on the other end of the shaft in a turbine housing. Typically the
turbine housing is formed separately from the compressor housing,
and there is yet another center housing connected between the
turbine and compressor housings for containing bearings for the
shaft. The turbine housing defines a generally annular chamber that
surrounds the turbine wheel and that receives exhaust gas from an
engine. The turbine assembly includes a nozzle that leads from the
chamber into the turbine wheel. The exhaust gas flows from the
chamber through the nozzle to the turbine wheel and the turbine
wheel is driven by the exhaust gas. The turbine thus extracts power
from the exhaust gas and drives the compressor. The compressor
receives ambient air through an inlet of the compressor housing and
the air is compressed by the compressor wheel and is then
discharged from the housing to the engine air intake.
One of the challenges in boosting engine performance with a
turbocharger is achieving a desired amount of engine power output
throughout the entire operating range of the engine. It has been
found that this objective is often not readily attainable with a
fixed-geometry turbocharger, and hence variable-geometry
turbochargers have been developed with the objective of providing a
greater degree of control over the amount of boost provided by the
turbocharger. One type of variable-geometry turbocharger is the
variable-nozzle turbocharger (VNT), which includes an array of
variable vanes in the turbine nozzle. The vanes are pivotally
mounted in the nozzle and are connected to a mechanism that enables
the setting angles of the vanes to be varied. Changing the setting
angles of the vanes has the effect of changing the effective flow
area in the turbine nozzle, and thus the flow of exhaust gas to the
turbine wheel can be regulated by controlling the vane positions.
In this manner, the power output of the turbine can be regulated,
which allows engine power output to be controlled to a greater
extent than is generally possible with a fixed-geometry
turbocharger.
Typically the variable-vane assembly includes a nozzle ring that
rotatably supports the vanes adjacent one face of the nozzle ring.
The vanes have axles that extend through bearing apertures in the
nozzle ring, and vane arms are rigidly affixed to the ends of the
axles projecting beyond the opposite face of the nozzle ring. Thus
the vanes can be pivoted about the axes defined by the axles by
pivoting the vane arms so as to change the setting angle of the
vanes. In order to pivot the vanes in unison, an actuator ring or
"unison ring" is disposed adjacent the opposite face of the nozzle
ring and includes recesses in its radially inner edge for receiving
free ends of the vane arms. Accordingly, rotation of the unison
ring about the axis of the nozzle ring causes the vane arms to
pivot and thus the vanes to change setting angle.
The variable-vane assembly thus is relatively complicated and
presents a challenge in terms of assembly of the turbocharger.
There is also a challenge in terms of how the unison ring is
supported in the assembly such that it is restrained against
excessive radial and axial movement while being free to rotate for
adjusting the vane setting angle. Various schemes have been
attempted for supporting unison rings, including the use of
rotatable guide rollers supported by the nozzle ring. Such guide
rollers complicate the assembly of the variable-vane assembly
because by their very nature they can easily fall out of or
otherwise become separated from the nozzle ring, since typically
they fit loosely into apertures in the nozzle ring.
BRIEF SUMMARY OF THE DISCLOSURE
The present disclosure relates to a variable-vane assembly for a
variable nozzle turbine such as used in a turbocharger, in which
the unison ring is radially and axially located with non-rotating
guide pins rigidly secured to the nozzle ring. In one embodiment,
the variable-vane assembly comprises a nozzle ring encircling an
axis and having an axial thickness defined between opposite first
and second faces of the nozzle ring, the nozzle ring having a
plurality of circumferentially spaced-apart first apertures each
extending axially into the first face and a plurality of
circumferentially spaced-apart second apertures that are
circumferentially spaced from the first apertures and each of which
extends axially from the first face to the second face. The
assembly also includes a plurality of vanes each having an axle
extending from one end thereof, the axles being received
respectively into the second apertures from the second face of the
nozzle ring and being rotatable in the second apertures such that
the vanes are rotatable about respective axes defined by the axles,
a distal end of each axle projecting out from the respective second
aperture beyond the first face. A plurality of vane arms are
respectively affixed rigidly to the distal ends of the axles, each
vane arm having a free end.
The setting angles of the vanes are changed in unison by a unison
ring having a radially inner edge defining a plurality of recesses
therein for respectively receiving the free ends of the vane arms.
The unison ring is positioned coaxially with the nozzle ring, with
a face of the unison ring opposing the first face of the nozzle
ring. The unison ring is rotatable about the axis of the nozzle
ring so as to pivot the vane arms, thereby pivoting the vanes in
unison.
One of the nozzle ring and the unison ring defines protrusions
extending toward and contacting the other so as axially space the
first face of the nozzle ring from the opposing face of the unison
ring by a first axial distance
The assembly also comprises a plurality of guide pins for the
unison ring, the guide pins being located radially inward of the
radially inner edge of the unison ring and each being inserted into
a respective one of the first apertures in the nozzle ring and
being rigidly affixed therein such that the guide pins are
non-rotatably secured to the nozzle ring with a guide portion of
each guide pin projecting axially from the first face of the nozzle
ring. The guide portion of each guide pin has a shank and defines a
shoulder that extends to a greater radius (relative to the axis of
the guide pin) than the shank. The shoulders of the guide pins are
axially spaced from the first face of the nozzle ring by a second
axial distance greater than the first axial distance. The shoulders
radially overlap the radially inner edge of the unison ring,
whereby the protrusions and the shoulders cooperate to constrain
axial movement of the unison ring and the shanks constrain radial
movement of the unison ring.
The guide pins can be secured to the nozzle ring by being press fit
into the first apertures in the nozzle ring, or by any other
suitable technique.
In one embodiment, the protrusions are integrally formed on the
nozzle ring. The protrusions can comprise bosses formed on the
nozzle ring, and each of the bosses can be located adjacent a
respective one of the first apertures in which the guide pins are
affixed. In accordance with one embodiment, each boss can surround
the respective first aperture.
In an alternative embodiment, the protrusions are integrally formed
on the unison ring. The unison ring can be formed by a stamping
process, and the protrusions can be formed during the stamping
process.
An advantage of the use of guide pins in accordance with the
present disclosure is that the pins can be of a simple shape that
can be manufactured without requiring any machining. For example,
the pins can be cold forged to their final shape.
In a further aspect of the present disclosure, vane arms are
rigidly affixed to the vane axles by a riveting process. The hole
in the vane arm that receives the associate vane axle has a conical
knurled portion at an upper side of the hole facing away from the
associated vane. The distal end of the axle is upset to generally
conform in shape to that of the conical knurled portion, thereby
achieving an interlocking between the arm and the axle, both
rotationally and along the axis of the axle.
BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING(S)
Having thus described the present disclosure in general terms,
reference will now be made to the accompanying drawings, which are
not necessarily drawn to scale, and wherein:
FIG. 1 is an exploded view of a first assembly that includes a
nozzle ring having spacers affixed thereto, a unison ring, and
guide pins, in accordance with one embodiment of the invention;
FIG. 2 is a perspective view of the first assembly of FIG. 1,
showing the guide pins fixedly secured in corresponding apertures
in the first face of the nozzle ring, with the unison ring captured
between bosses on the nozzle ring and shoulders on the guide
pins;
FIG. 3 is an exploded view of a second assembly including the first
assembly of FIG. 2 (shown inverted relative to FIG. 2) together
with a plurality of vanes;
FIG. 4 is a perspective view of the second assembly of FIG. 3;
FIG. 5 is a perspective view of a third assembly including the
second assembly of FIG. 3 and a turbine housing insert;
FIG. 6 is an exploded view of a fourth assembly that includes the
third assembly of FIG. 5 (shown inverted relative to FIG. 5)
together with a plurality of vane arms;
FIG. 7 is a perspective view of the fourth assembly of FIG. 6 in
its final assembled condition;
FIG. 8A is a perspective view of a unison ring for use in an
alternative embodiment of the present invention;
FIG. 8B is a view similar to FIG. 8A, with the unison ring inverted
relative to FIG. 8A;
FIG. 9 is a perspective view of a variable-vane assembly using the
unison ring of FIGS. 8A and 8B, showing the unison ring partially
broken away for clarity of illustration
FIG. 10 is a perspective view of the variable-vane assembly of FIG.
9;
FIG. 11 is an exploded view of a vane and vane arm in accordance
with one embodiment;
FIG. 12 is a view of the vane and vane arm of FIG. 11 in an
assembled state prior to riveting; and
FIG. 13 is a view of the vane and vane arm after riveting.
DETAILED DESCRIPTION OF THE DRAWINGS
The present invention now will be described more fully hereinafter
with reference to the accompanying drawings in which some but not
all embodiments of the inventions are shown. Indeed, these
inventions may be embodied in many different forms and should not
be construed as limited to the embodiments set forth herein;
rather, these embodiments are provided so that this disclosure will
satisfy applicable legal requirements. Like numbers refer to like
elements throughout.
FIG. 1 shows an exploded view of a first assembly illustrating the
initial steps in the operation of assembling a variable nozzle
assembly in accordance with one embodiment of the present
invention. FIG. 2 shows the first assembly in its assembled
condition. The first assembly includes a nozzle ring 20 with a
plurality of guide pins 22. The nozzle ring has a plurality of
circumferentially spaced first apertures 24 extending into a first
face of the nozzle ring for receiving the guide pins. More
particularly, each guide pin has a generally cylindrical end
portion 23 of relatively small diameter that is sized to fit into a
corresponding first aperture 24 with an interference fit. The end
portions 23 of the guide pins 22 are press-fit into the first
apertures 24, such that guide portions of the guide pins project
axially from the first face of the nozzle ring as shown in FIG. 2.
The guide portion of each guide pin includes a shank 25 of larger
diameter than the end portion 23, and a shoulder 26 of larger
diameter than the shank 25. The end of the shank 25 of each guide
pin abuts a raised boss 21 on the first face of the nozzle ring
when the end portion 23 of the guide pin is fully inserted into a
respective first aperture 24. In the illustrated embodiment, there
are five guide pins 22 spaced approximately uniformly about the
circumference of the nozzle ring, although a different number of
guide pins could be used. As illustrated, the bosses 21 are
adjacent the first apertures 24, and can (but do not have to)
surround each first aperture 24.
The guide pins 22 can be made by a cold-forging process or any
other suitable process.
The first assembly also includes a unison ring 30. The unison ring
has a radially inner edge 32 that is smaller in diameter than the
maximum diameter defined collectively by the shoulders 26 of the
guide portions of the guide pins 22. In other words, the shoulders
26 of the guide pins radially overlap the radially inner edge 32 of
the unison ring. The largest diameter collectively defined by the
shanks 25 of the guide pins is very slightly smaller than or about
equal to the diameter of the inner edge 32 of the unison ring 30.
Accordingly, the unison ring is located relative to the guide pins
such that the inner edge 32 of the unison ring is captive (in the
axial direction) between the shoulders 26 of the guide pins and the
bosses 21 on the nozzle ring 20. The bosses 21 space the unison
ring 30 from the major planar face of the nozzle ring 20 by a first
axial distance. The shoulders 26 of the guide pins 22 are axially
spaced from the face of the nozzle ring by a second axial distance
greater than the first axial distance by an amount sufficient to
accommodate the thickness of the unison ring 30 between the
shoulders and the bosses, but not so great as to allow any
significant axial play of the unison ring, thereby restraining the
unison ring against axial movement. At the same time, the shanks 25
of the guide pins 22 restrain the unison ring against radial
movement relative to the nozzle ring.
With reference to FIG. 3, a second assembly is depicted in exploded
view. FIG. 4 shows the second assembly in its assembled condition.
The second assembly includes the first assembly of FIG. 2 (shown
inverted relative to FIG. 2) together with a plurality of vanes 40.
Each vane 40 has an axle 42 rigidly affixed thereto. The axles 42
are inserted through corresponding second apertures 28 in the
nozzle ring 20, which apertures 28 extend entirely through the
nozzle ring from the first face to an opposite second face thereof.
The axles 42 are inserted into the apertures 28 from the second
face, and distal ends 43 of the axles extend slightly beyond the
first face (see FIG. 6). Each first aperture 24 is located,
circumferentially, between two of the second apertures 28. The
first apertures 24 are located at a greater radius than the second
apertures 28, relative to the axis of the nozzle ring 20.
Also visible in FIGS. 3 and 4 are three spacers 60 rigidly affixed
to the nozzle ring 20 and projecting axially from the second face
of the nozzle ring for engagement with a turbine housing insert 70
(FIG. 5). The turbine housing insert 70 has three apertures for
receiving end portions of the spacers 60. The spacers have
shoulders or radial bosses that abut the second face of the nozzle
ring 20 and the opposite face of the insert 70 so as to dictate the
axial spacing between these faces. The spacers are rigidly affixed
to the nozzle ring and insert, such as by orbital riveting or any
other suitable process. The turbine housing insert 70 is configured
with a tubular portion 74 to be inserted into the bore of a turbine
housing in a turbocharger. The nozzle ring 20 and insert 70
cooperate to form a passage therebetween, and the variable vanes 40
are arranged in the passage and preferably extend in the axial
direction fully across the passage so that fluid flowing through
the passage is constrained to flow through the spaces between the
vanes. FIG. 5 shows a third assembly comprising the second assembly
of FIG. 4 assembled with the turbine housing insert 70.
With reference to FIG. 6, a fourth assembly is shown in exploded
view, comprising the third assembly of FIG. 5 together with a
plurality of vane arms 44. The setting angles of the vanes 40 are
changed by rotating the vanes about the axes defined by the vane
axles 42, whereby the vane axles rotate in their respective second
apertures 28 in the nozzle ring 20. A vane arm 44 is engaged with
the distal end 43 of each vane axle 42. Each vane arm has a free
end 46 that is engaged in a recess 34 in the inner edge of the
unison ring 30. The vanes 40 are positioned such that all of the
vanes have the same setting angle, and then the vane arms are
rigidly affixed to the distal ends 43 of the axles 42, such as by
welding, or by a riveting process described further in connection
with FIGS. 11-13. FIG. 7 shows the fourth assembly in its assembled
condition. Rotation of the unison ring 30 about its central axis
causes the vane arms 44 to pivot, thereby pivoting the vanes 40 in
unison.
The entire variable-vane assembly of FIG. 7 forms a unit that is
installable into the turbine housing bore. The turbine housing is
then connected to a center housing of the turbocharger such that
the variable-vane assembly is captured between the turbine and
center housings.
In accordance with one embodiment of the present invention,
therefore, the variable-vane assembly allows the assembly process
to be eased and simplified and the manufacturing cost of the
assembly to be reduced. In particular, the nozzle ring 20 can be
formed with the bosses 21 integrally formed thereon, and the
provision of the bosses 21 allows the guide pins 22 to have a
simple structure that can be made without machining (e.g., by cold
forging). More specifically, because the bosses 21 space the unison
ring 30 away from the nozzle ring by the desired axial spacing,
this function does not have to be performed by the guide pins 22.
Thus, the guide pins need only a single shoulder 26, for
restraining axial movement of the unison ring away from the nozzle
ring. Regarding the nozzle ring 20, it can be made by hot forging
the ring to near net shape, followed by cold forging to calibrate
(fine-tune) the shape, wherein the bosses 21 are formed to their
final shape during the forging process. Precision machining of the
nozzle ring is required only on its inner diameter and on the face
that is adjacent the vanes 40.
The embodiment described above employs bosses 21 (i.e.,
protrusions) on the nozzle ring 20 for spacing the unison ring 30
from the nozzle ring. In an alternative embodiment as shown in
FIGS. 8A, 8B, 9, and 10, the protrusions can be formed on the
unison ring. Thus, FIGS. 8A and 8B illustrate an alternative unison
ring 130 that is generally similar to the previously described
unison ring 30, except that it includes a plurality of protrusions
131 that extend from one of the substantially planar faces of the
ring. The protrusions can be formed in any suitable fashion. One
possibility is to form the unison ring by stamping, and to form the
protrusions during the stamping process, although the embodiments
of the invention employing the unison ring 130 are not limited to
any particular manufacturing process for the ring. The protrusions
131 essentially serve the same function as the bosses 21 on the
nozzle ring 20 in the previously described embodiment, namely, to
axially space the unison ring 130 from the adjacent nozzle ring by
a desired distance dictated by the height of the protrusions.
A variable-vane assembly in accordance with this embodiment of the
invention is depicted in FIGS. 9 and 10, the unison ring 130 being
partially broken away in FIG. 9 for clarity of illustration. The
parts in FIGS. 9 and 10 bearing the same numbers as the previous
embodiment have essentially the same structure and function as in
the previous embodiment and hence their description is not repeated
here. The nozzle ring 120 is substantially similar to the
previously described nozzle ring 20, except that it lacks bosses
because the protrusions 131 on the unison ring 130 perform the
function of the bosses. In other respects, the variable-vane
assembly is substantially like the previous embodiment.
As noted previously, the fixation of the vane arms 44 to the ends
43 of the vane axles 42 in some embodiments of the present
invention can be performed by a process of orbital riveting rather
than welding. One of the challenges in affixing the vane arms to
the vane axles in any variable-vane assembly is ensuring that all
vane/vane arm assemblies have the same orientation, in the
rotational sense about the axis of the vane axle, between the vane
and the vane arm. Additionally, it is always an objective to
provide a sufficiently high breaking torque (i.e., the torque that
must be exerted on the vane arm relative to the vane axle in order
to break the axle/arm bond). While these objectives could be
achieved by making the end of the vane axle in a non-round shape
and making the hole in the vane arm correspondingly shaped, such an
approach would not allow any flexibility in the relative
orientation of the vane arm and axle. Thus, for example, if the
assembler wanted to fine-tune the relative orientation in order to
calibrate the vane setting angles, the non-round shapes of the axle
and hole would not allow such fine tuning.
In accordance with one embodiment of the invention, the objectives
of high breaking torque and ability to fine-tune the vane arm
orientation are achieved by a conical knurled riveted joint
illustrated in FIGS. 11-13. The ends 43 of the vane axles 42 are
generally circular cylindrical in shape. The hole in the vane arm
44 has a conical knurled portion 48 at the upper side of the arm
(i.e., the side that will face away from the vane 40 after
assembly). The knurled portion 48 defines a plurality of radially
inwardly projecting teeth 49 spaced apart about the inner
circumference of the hole. The smallest diameter collectively
defined by the teeth is substantially equal to or very slightly
larger than the outside diameter of the axle end 43. FIG. 12
illustrates that in a first step, the end 43 of the vane axle 42 is
inserted through the hole in the vane arm 44. Because of the
circular shape of the axle end 43, the vane arm 44 can be rotated
relative to the axle 42 by any desired amount, and in particular
can be adjusted by an amount less than the angular spacing between
the teeth of the knurled portion 48, if such is required in order
to fine-tune the relative orientation of the arm. As shown in FIG.
13, the axle end 43 is then upset or deformed by a suitable
riveting tool such that the material of the end 43 is caused to
generally conform to the conical shape of the knurled portion 48
and is caused to intrude into the spaces between the teeth of the
knurled portion 48, thereby achieving an interlocking effect (both
rotationally and along the axis of the axle) between the arm and
the axle.
Many modifications and other embodiments of the inventions set
forth herein will come to mind to one skilled in the art to which
these inventions pertain having the benefit of the teachings
presented in the foregoing descriptions and the associated
drawings. Therefore, it is to be understood that the inventions are
not to be limited to the specific embodiments disclosed and that
modifications and other embodiments are intended to be included
within the scope of the appended claims. Although specific terms
are employed herein, they are used in a generic and descriptive
sense only and not for purposes of limitation.
* * * * *